Buying and renting property can be a lucrative business and can make you some good income.
People will always need a home to live in and will pay what they have to or can to rent a house or apartment from you.
So if you can purchase the property cheap enough and bring in enough rent to cover the mortgage plus have profit for yourself after paying the mortgage then you stand to make some good money renting property.
It's also better if you can purchase the house or apartment in cash although that's hard to do unless the place is cheap enough or you have the funds available to do so.